Underreamer



1952 J. cs. BRODHEAD ET AL 2,621,893

UNDERREAMER Filed Nov. 16, 1948 \JANES G. BRODHEAD STEWART R RODDY i atented Dec. 16, 1952 UNDERREAMER James G. Brodhead and Stewart P. Roddy, Allen, Tex.

Application November 16, 1948, Serial No. 60,292

14 Claims. 1

This invention relates to new and useful improvements in underreamers.

One object of the invention is to provide an improved underreamer of economical, rugged construction for efiiciently enlarging the lower ends of bore holes which are adapted to receive concrete piers or underfootings.

Another object of the invention is to provide an improved underreamer having cutters adapted to beejected. for enlarging the lower portion of a previously formed bore hole and being retractable to permit insertion and withdrawal of the underreamer, there being means for positively ejecting and retracting the cutters and holding the same in adjusted positions.

A further object of the invention is to provide an improved underreamer having a bucket with cutters of the shape of the desired undercut and mounted on verticall pivoted deflectors which form a part of the bucket, whereby the cutters may be swun laterally outward to gradually enlarge the lower portion of a bore hole and the cut materials are directed into the bucket by the deflectors.

Still another object of the invention is to provide an improved underreamer, of the character described, having gear sectors and a pinion for ejecting and retracting the cutters and worm for imparting rotation to the pinion whereby the position of said cutters may be positively and accurately controlled.

A construction designed to carry out the invention will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawing, wherein an example of the invention is shown, and wherein:

Fig. 1 is a perspective view of an underreamer constructed in accordance with the invention,

Fig. 2 is a transverse, vertical, sectional view of the underreamer bucket, showing one cutter partially ejected,

Fig. 3 is a perspective view of the bucket, with portions broken away and the cutters ejected,

Fig. 4 is a vertical, sectional view, taken on the line 4-5 of Fig. 1, showing the worm and its coacting pinion,

Fig. 5 is a transverse, vertical, sectional view, taken at a right angle to Fig. 3,

Fig. 6 is an underside plan View of the bucket, and

Fig. '7 is a horizontal, cross-sectional view, taken on the line 7-1 of Fig. 5.

In the drawing, the numeral [0 designates a cylindrical casing or bucket having a fiat bottom H with an axial, tapered pilot pin l2 and radial scrapers [3. The latter are formed by slitting the bottom and bending portions downwardly at an angle and sharpenin their edge portions, whereby loose dirt at the bottom of a bore hole is directed into the bucket. A pair of verticallyalined cross bars 14 and I5 extend diametrically across the open, upper end of the bucket ill in spaced relation, bein welded or otherwise secured to the wall of said bucket. The upper bar [4 has an upright hollow drive stem or sleeve [6 connected to the center thereof by a collar l1 and the usual cross arm or head [8 is fastened to the top of the drive stem by a T 19 for turning the bucket. Obviously, the stem l6 and cross head l8 coact to provide a handle for the underreamer bucket.

Diametric slots or openings 20 are formed in the side wall of the bucket and the same extend vertically from the bottom to a point substantially midway the height of the bucket for receiving verticall arced or curved cutters or blades 2|. The latter are welded or otherwise secured to the ends of horizontally curved doors or deflectors 22 which are preferably cut from the bucket wall so as to provide inlet openings 23 that merge with the slots 20 for admitting dirt into the bucket. In efiect, each slot and its merging opening form a continuous or single opening in the bucket. As most clearly shown in Figs. 3, 5 and 6, the deflectors 22 have the same curvature as the bucket wall and their upper edges are inclined downwardly toward the blades 2| whereby the wider ends of said deflectors are spaced from said blades. Upright shafts or posts 2A extend between and are journaled in the ends of the lower cross bar I 5 and underlying lugs or ears 25 adjacent the wider ends of the openings 23 and the wide ends of the deflectors are Welded or otherwise secured thereto so as to be pivotally supported. Thus, the deflectors do not extend above the blades when the same are ejected or swungoutwardly. It is noted that the outer portion of each blade extends substantially vertical, parallel to the narrow end of its deflector and that its intermediate portion is swung in an arc about a horizontal axis, terminating in an upper inclined portion. The outer or free longitudinal margin of each blade is preferably sharpened.

For swinging the deflectors so as to eject and retract the blades, a pair of gear sectors or quadrants 26 are disposed between the bars 14 and I5 in meshing engagement with an axial 3 pinion 21 and each gear sector is secured on the upper end of one of the shafts 24 which projects through said bar [5. The pinion 21 is adapted to be oscillated by a shaft or post 28 which depends axially within the sleeve l6 and has its lower end journaled in and extending through the bar 14. Mounted upon the upper end of the shaft 28 which projects through the T [9 is a pinion 29 in constant mesh with a worm 30 (Fig. 4). A suitable bracket 3| is carried by the T for supporting the worm 30 and a crank 32 is provided for turning said worm. For reinforcing the blades, a short rod or arm 33 connects the inner end of each blade to the gear sector mounted upon the shaft of its deflector (Figs. 2 and If desired, a horizontal shoe or a lip 34 may be welded or otherwise secured to the inner surface of each deflector at its lower edge portion for preventing the deflectors and blade from digging into the bottom of the hole and increasing the depth of said hole. The shoes 34 are in the form of small plates and are disposed within the bucket when the deflectors are swung inwardly.

Manifestly, rotation of the worm causes ejection and retraction of the blades due to this arrangement. Oscillation of the pinion 29 is transmitted by the shaft 28 to the pinion 21 so as to turn the sectors 28 and their shafts 24 about their axes. When turned in a counter-clockwise direction, the deflectors 22 are swung outwardly to eject or move the blades 2| outwardly. Retraction of the blades is accomplished by a reverse rotation or turning of the aforesaid parts. Due to the provision of the worm, the blades may be ejected gradually and positively held in fixed positions. The curvature of the blades is such that the lower portion of a bore hole is gradually enlarged by continued rotation of the bucket nd ejection of said blades. The loose dirt in the bottom of the hole is scooped up and directed into the bucket by the scrapers 13, while the dirt or material cut by the blades is directed into said bucket by the deflectors. It is noted that the scrapers flatten the bottom of the hole by removing earth left by the usual auger. When the blades are retracted, the openings 23 are closed by the deflectors and said blades partially close the slots 2i. Thus, the cut material or dirt is retained in the bucket and is removed upon withdrawal of said bucket from the hole. Since the open upper end of the bucket is not materially obstructed, said bucket may be emptied by inverting the same; however, if desired or necessary, the worm may be rotated so as to swing the deflectors outwardly and permit discharge of the dirt through the openings 23. It is manifest that the bottom of a bore hole may be flattened by the herein described underreamer as well as have its lower portion enlarged. Due to the curvature of the deflectors, the blades are ejected in substantially straight paths upon outward swinging of said deflectors.

Since the upper portion of each blade extends inwardly and upwardly into the bucket in spaced relation to its deflector, an opening or passage is provided therebetween for receiving and directing dirt cut by the blade into said bucket through its opening. This arrangement prevents the dirt from passing over and packing behind the deflector. Due to the arms or rods 33 connecting the inner, upper ends of the blades to the gear sectors 28, swinging of the deflectors and blades is facilitated.

The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.

What we claim and desire to secure by Letters Patent is:

1. In an underreamer, a bucket having an opening in its side wall, a deflector pivotally mounted on a substantially vertical axis adjacent the opening and normally disposed in said opening, a substantially upright cutter mounted on the deflector with its upper portion extending inwardly and upwardly in spaced relation to said deflector so as to project through the opening into the bucket when said deflector is swung outwardly to provide a dirt passage between the upper portion of the cutter and deflector, and means having connectlon with upper portion of said deflector for swinging the same about its axis outwardly away from and inwardly toward said opening so as to eject and retract the cutter, the shape of the cutter forming an enlargement in the lower portion of a hole upon rotation of the bucket with the enlargement increasing toward the lower end of the hole.

2. In an underreamer, a bucket having an opening in its side wall, a deflector pivotally mounted on a substantially vertical axis adjacent the opening and normally disposed in said opening, a substantially upright cutter mounted on the deflector with its upper portion extending inwardly and upwardly in spaced relation to said deflector so as to project through the opening into the bucket when said deflector is swun outwardly to provide a dirt passage between the upper portion of the cutter and deflector, and gear means mounted in the upper end of the bucket and having positive connection with the upper portion of said deflector for swinging the same about its axis outwardly away from and inwardly toward said opening so as to eject and retract the cutter.

3. In an underreamer as set forth in claim 2, a supporting shoe carried by the deflector for engaging the bottom of a hole to prevent penetration of the underreamer.

4. In an underreamer, a bucket having an opening in its side wall, a deflector pivotally mounted on a substantially vertical axis adjacent the opening and normally disposed in said opening, a substantially upright cutter mounted on the deflector with its upper portion extendin inwardly and upwardly in spaced relation to said deflector so as to project through the opening into the bucket when said deflector is swung outwardly to provide a dirt passage between the upper portion of the cutter and deflector, gear means mounted in the upper end of the bucket and having positive connection with the upper portion of said deflector for swinging the same about its axis outwardly away from and inwardly toward said opening so as to eject and retract the cutter, a handle connected to the bucket for rotating the same, and means carried by the handle for actuating the gear means.

5. In an underreamer, a bucket having an opening in its side wall, a deflector pivotally mounted on a substantially vertical axis adjacent the opening and normally disposed in said opening, a substantially upright cutter mounted on the deflector with its upper portion extending inwardly and upwardly from said deflector so as to project through the opening into the bucket when said deflector is disposed in said opening, gear means mounted in the upper end of the bucket and having connection with said deflector for swinging the same about its axis outwardly away from and inwardly toward said opening so as to eject and retract the cutter, a handle connected to the bucket for rotating the same, the handle including a sleeve, a shaft within the sleeve connected to the gear means, and means carried by the handle for imparting rotation to for actuating th gear means.

6. In an underreainer, a bucket hav' opposed openings in its side wall adjacent botto. a deflector pivotally mounted on a substantially vertical axis adjacent each opening and normally closing the opening, a substantially upright cutter mounted on the outer end of the deflector and having its upper portion curved upwardly and inwardly so as to project through said opening into the bucket when said deflector is closing said opening, a gear sector at the upper end of said bucket having connection with each defiector, a pinion meshing with the sectors, a handle connected to said bucke for rotating the same, the handle including a sleeve, a shaft extending axially through the sleeve and connected to the pinion, a second pinion on the upper end of the shaft, and a worm carried by the upper end of the handl and meshing with he second pinion for imparting rotation to the pi -ions so as to turn the gear sectors and swing the deflectors about their axes away from and toward said bucket so as to eject and retract the cutters.

7. In an underreanier as set forth in claim 6 an arm connecting the inner end of each cutte' to the gear sector of its respective deflects 8. In an underrearner as set forth in claim 6, a shoe carried by each deflector for engaging the bottom of a hole to prevent penetration of the underreamer.

9. In an underrearner, a bucket having an opening in its side wall, a deflector pivotally mounted on a substantially upright axis adjacent the openin and disposed in said opening when retracted, a cutter mounted on th deflector, gear means mounted in the upper end of the bucket and having connection with said deflector for swinging the same about its axis outwardly away from and inwardly toward said opening so as to eject and retract the cutter, a handle connected to the bucket for rotating the same, the handle including a sleeve, a shaft within the sleeve and connected to the gear means, and means carried by said handle for imparting rotation to the shaft for actuating said gear means.

10. In an underrearner as set forth in claim 9, a shoe carried by the deflector for engagin the bottom of a hole to prevent penetration of the underreamer.

ii. In an underrearner, a bucket having an opening in side wall, a deflector mounted on a substantially upright axis adjacent the opening and disposed in said opening when retracted, a substantially upright cutter mounted on the de doctor with its upper portion extending inwardly upwardly through said opening into the bucket when said deflector is swung outwardly, means having connection with said deflector to swin deflector about its axis outwardly away from and inwardly toward said opening and thereby eject and retract the cutter, and means connecting the upper portion of said cutter to the swinging means, the shape of said cutter formin an enlargement in the lower portion of hole upon rotation of the bucket with th enlargement increasing toward the lower end of the hole.

12. In an underreamer, a bucket having an opening in its side wall, a deflector, a substantially upri ht shaft pivotally supporting the deflector the opening, a cutter mounted on said deflector, and means having positive connection with the shaft to turn said shaft upon its axis and swing said deflector outwardly away from and inwardly toward said opening so as to eject and retract the cutter.

13. In an underrearner as set forth in claim 12 wherein the swinging means has connection with the upper portion of the shaft whereby the interior of the bucket is substantially unobstructed.

14. In an underreamer as set forth in claim 12 wherein the cutter is substantially upright and has its upper portion extending inwardly and upwardly in spaced relation to said deflector to provide a dirt passage between the upper portion of said cutter and defl ctor when said deflector is swinging outwardly.

JANES G. BRODHEAD. STEWART P. RODDY.

REFERENCES CETEIB The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 469,290 Whipple Feb. 23, 1892 1,236,940 Huesselmann Aug. 14, 1917 1,478,306 Sweetinan Dec. 18, 1923 1,905,995 Bertran Apr. 25, 1933 1,926,325 Eertran Sept. 12, 1933 

